Method of manufacturing electrically-welded tubing



R. STRESAU.

METHOD OF MANUFACTURING ELECTRICALLY WELDED TUBING.

'APPLICATION FILED JULY'I], I920.

mama Nov. 16, 1920.

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ATTORNEY:

R. STRESAU.

7 METHOD or MANUFACTURING EVLECTRIGALLY WELDED TUBING.

APPLICATION FILED JULY 11, I920, 1,359,001. PawntedNov. 16,1920. 1

2 SHEETS-SHEET Z.

UNITED STATES PATENT oFFIcE.

3101mm) sra'EsAU, or WAUWAUTOSA, WISCONSIN, ASSIGNOR To A. ,0. SMITH roaarron, or MILWAUKEE, wIsooNsIN, A CORPORATION OF NEW YORK,

METHOD or MANUFACTURING ELECTRICALLY-WELDED TUBING.

Specification of Letters Patent.

Patented N 0V. 16, 1920.

Application filed July 17, 1920. Serial No. 396,883.

To all whom it may concern:

Be itknown that I, RICHARD STREsAU, a citizen of the United States, and a resident of the city of .Wauwautosa, in the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Improvement in Methods of Manufacturing Electrically-Welded Tubing, (Case #160,) and I do declare the following to be a full, clear,

and exact description thereof, such as will enable others skilled in the art of making welded tubing to practice my invention, reference being had to the accompanying drawings as illustrating some forms of mecha-.

nisms designed to carry my improved method into effect.

The invention relates to the process of manufacturing metal tubes.

The inventionrelates particularly to the process of manufacturing electrically welded tubes, in which an elongated tubularv with the meeting edges thereof united by an elelparic welding operation, to complete the The present ractice of thus making electrically welded tubes has been performed very satisfactorily, ,but an objection has arisen in applying such present practice to the production of tubes composed of stock of considerable gage. In forming the tubu lar section by pressing or rolling the blank into shape, the edges thereof arefound in some cases to abut so closely that the seam is practically closed, and the electric arc in fusing the said edges is required to transmit its welding temperature from the outer surface of the tube. This practice requires the use of a current of very high ampere e, in order that the remoter material at t e welding line may be properly heated and brought to the desired state of fusion.

I In the course of some experimentations in the field of electric welding, I have discovered that the welding operation described may be erformed with much greater facility, if t e parts constituting the joints to' permitted to play in the space between the separated edges or faces of the work, and

- thus heat such faces by direct application,

subjecting the tubular structure to a wedg:

ing action, which latter will serve to slightly separate the edges so as to expose the opposite faces thereof, and leave a longitudinal opening or space, in which the electric arc may be played, to fuse the said edges or faces. The arcing current is transmitted b means of a destructible metallic electrode, WlllCh is fused coincidentally with the fusing of the local areas of the parts to be welded. The fused metal flowing from the said electrode is carried by'the are into the open joint in a quantity sufficient to completely fill the opening or space between the edges, produce a perfectly welded joint, which, along the welded line, will have a thickness not less than that of the partsto be welded, so that a tube of uniform cross sectional construction will be produced.

The novelty of my invention will be polnted out in the appended claims.

The drawings which accompany this specification diagrammatically illustrate the succession of operations performed in roducing a tubular section of uniform diameter from a metal strip or late.

In such drawings, igure 1 shows a pair of stamping dies, which, in the first step in the operation of producing the tube, are adapted to change the cross sectional area of a metal strip by imparting a lengthwise groove to the same. v

Fig. 2 shows an end view, or it may be a section, of the trough like or U shaped strip, after the latter has been subjected to the igl. 3' illustrates a set of dies for performing t e second step in the process, and also the conversion of the trough like strip of Fi 2, into an irregular tubular structure.

ig. 4 shows a set of dies, the operation of which completes the structure by exerting pressure upon the irregular tube shown in Fig. 3, and perfecting the cylindrical contour of the tube, the meeting edges'of which are pressed into such close engagement as to practically close the joint or seam.

Fig. 5 shows a simple means for producing a slight separation of the meeting edges of the tube, formed as in Fig. 4, to provide a space or gap wherein which the electric arc may play, so that such edges may be fused at the same time that the arc is producing a welding temperature along the welding line.

Fig. 6 is an end view, or it may be a sec tion, of the tubular section shown in Fig. 4, with its meeting edges slightly separated. for the purpose and in the manner described.

Fig. 7 is an end view, or it may be a section, of the tubular section as. it appears upon completion of the welding operation.

Figs. 8 and 9 are respectively a side view and front view of a machine provided with a rotating wedge which is adapted'to pro duce the separation between the edges of the tube, as the latter is fed through the said machine.

Figs. 10 and 11 are respectively a side view and an end view of 'wedging devices employed in a press, for separating the edges of the tube.

Fig. 12 is a fragmentary view illustrating a preparatory provision of means to permit the initial entry of the wedge between the meeting edges of the tubular structure to be welded, and facilitate the separation of such ed es.

eferring now to the drawings, Fig. 1 shows a pair of ordinary stamping dies 10 and 11, which by their action in well known manner, are adapted to convert the sheet metal strip, or blank 12, into the cross sectional grooved form 120, shown in Fig. 2. The grooved strip 120 is then placed between a second pair of stamping dies 13 and 14, having the formation illustrated. in Fig. 3,

. and by-means of which dies the said strip is caused to assume what is approximately a tubular formation. formed with a head 15, which is supported by a thin neck piece 16, extending the length of the head 15. By the operation of the dies 13 and 14, the grooved blank 120 will be converted into an approximately tubular structure 121, but with the edges sufficiently separated to permit the structure 121 to be pulled lengthwise from about the head 15. The hollow die member 14 is shaped to correspond with the head 15, and the shape of the dies 13 and 14, is such as to produce plane surfaces on opposite sides of the structure 121. In the third operation, the structure, 121 is placed between two semi-circular stamping dies 17 and 18, which act to further change the configuration ofthe member 121, and produce a cylinder 122, of uniform diameter. The displacement of the plane surfaces 123, resulting from the pressure exerted by the semi-circular dies 17 and 18, g

The die member 13 is causes the metal to flow so as to follow the contour of the said dies and perfect the cylindrical outline of the tube 122. The pressure thus exerted caused the meeting edges to engage each other so that the joint is practically closed.

he welding current is transmitted to the edges of the work to be welded by means of a destructible electrode 19, of usual construction. By reason of the joint at the edges bemg closed, it is required that the are at the point of the electrode, heat the metal entirely through from the outer side, and this requires the application of a current of high amperage for a period longer than would be necessary, were the arc permitted to act upon the edges of the work, as well as the outer surface thereof To facilitate the operation of fusing the work, I propose to separate the meeting edges which have been compressed into engagement with each other by the dies of the forming press, so that the arc may play in the opening formed by such separation, and thus quickly create a fusing temperature 111 the work, by acting directly upon the separated edges thereof.

' The separation of the edges of the work for the purposes of my invention, may be produced by any convenient means A simple means for enabling this separation to be effected, resides in a wedge shaped die or blade 20, such as is illustrated in Figs. 5, 10 and 11, which may be forced into the seam 1n the tube 125, the latter being pillowed in a support 21, Flg. 11, So as to produce a longitudinal opening or gap 126, in the tubular section 127, F 1g. '6.

Although the means referred to is effect1ve,it is not suitable for rapid production, and for the latter purpose, I have devised a. special machine of the form illustrated in Figs. 8 and 9. The said machine is composed of a frame 22, in which is journaled shaft 23 and 24. The shaft 23 drives a curved feeding roller 25, designed to feed the tubular sections in succession to the wedging device with rapidity. The shaft 24 carries a circular wedge 26, which will force its rotating edge into the seam of the tube and create a separation or gap of the desired width. The shaft 24 is mounted in adjustable bearings 27, by means of which the effective edge of the rolling wedge 26 Ina *be adjusted to o erate upon tubes of di erent diameter. he construction described enables the tubes to be fed with great 'ra idity through the machine.

hen tapering tubular structures, such as is indicated by the dash and dot line 25, in Fig. 8,.are being manufactured, the effective edge 29 of the rolling wedge may be formed as a spiral, the lesser radius of the spirally formed rotating wedge entering the seam at the larger end of the tube.

at the welding lin'e.

. an open space the lengt operation and will automatically adjust the tube upon its support in proper position for the further operation of the wedging means, as the latter forces the meetingedges of the tubular section apart to provide the desired space or gap in which the electric arc may play, to effectively fuse the metal from one side to the other, and produce in the cylinder 128, a perfectly welded joint, as indicated at 129, in Fig. 7. The best results will be obtained by employing a chill or cooling device of usual construction, during the operation of welding. The fused metal flowing from the destructible electrode will fill the space, or gap by which the edges of the work are separated, and produce a joint of a thickness equal at least to the gage of the sheet from which the tube is formed.

Having thus described my invention, what I claim and desire to secure by Letters Pat ent of the United States, is:

1. The method of making electrically welded tubing,-which comprises the ste s of forming a metal strip into a tube wit the meeting edges'thereof in abutting contact, separating the said edges so as to rovide an open space the len h of the tu e, and

fusing the said edges y means of an electric arc.

2. The method of -making electrically welded tubing, which comprises the ste s of forming a metal strip into a tube wit the meetin edges thereof in abutting contact, separating the said ed es so as to provide T1 of the tube, fusing the said ed es by means of an electric arc and filling t e said space with molten metal to erfect the 'oint.

. The met 0d of ma electrically welded tubing, which comprises the steps of forming a metal strip into a tube with 1 the meeting ed es thereof in abutting contact, wedging t e said ed es apart so as to provide an open space t e length of the tube, and fusing a current conducting electrode in the said open space, to fill the latter and complete the welded joint.

4. The method of making electrically welded tubing, which consists in forming a metal strip into a tube with the meeting edges thereof in abutting contact, wedging the said ed es apart so as to provide an open space t e length of the tube, conducting an electric current to the work by means of a destructible electrode to fuse the said edges, and simultaneously filling the said s ace with the molten metal flowing from t e said electrode.

5. The method of making electrically welded tubing, which consists in separating the meeting edges of a rolled tubular structure so as to provide an open space, fusing. the said edges by means of an electric are playing in the said open space and simultaneously filling such open space by molten metal flowing from a fusible vconducting electrode.

6. The method of making electrically welded tubing, which consists in bending a stri of metal into a trough, pressing the 'troug into a tube open at one side, then I closing the said opening to complete the cylindrical contour of the tube and bring the meeting edges thereof in abutting contact, wedging the said edgps apart to provide an open space the lengt of the tube, conducting an electric current to the said edges by means of a destructible electrode to fuse the latter, and filling the open space with metal flowing from the. fusing electrode.

In testimony whereof, I have signed my name at Milwaukee, this 14" day of July,

R. STRESAU. 

